The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A memory device may comprise a memory device controller and memory. The memory may be composed of different types of memory, such as volatile memory (e.g., random access memory) and non-volatile memory (e.g., NAND flash memory). In particular, the non-volatile memory may be composed of memory cells that can be programmed to store a single bit or a single level, being termed a single-level cell (SLC) whereas other memory cells may be programmed to store multiple bits or multiple levels, being termed multi-level cells.
When the memory device receives data from a host device, the memory device may first program the data into volatile memory (e.g., a RAM portion assigned for use by the memory device controller). Then, the memory device controller may program the data from volatile memory into SLC memory. Subsequently, the data stored in SLC memory may be moved or copied to MLC memory. For example, data stored in one or more of the SLC pages (or blocks) may be folded to one or more of the MLC pages (or blocks). As an example, where an MLC stores three bits per cell (e.g., X3), data stored in three SLC pages may be copied to a single MLC page. More particularly, an MLC page may store data from three SLC pages, where the data is stored in upper, middle, and lower pages of the MLC page. Thus, the moving or copying of data from SLC memory to MLC memory (or from one or more SLC pages (or blocks) to one or more MLC pages (or blocks)) may be referred to as a folding operation.